<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		
		<script>
					
					
					// 1. 数组
					var arr1 = new Array();
					console.log(arr1.length)
					
					arr1[0] = "张三";
					arr1[1] = 1;
					arr1[2] = "王五"
					console.log(arr1)
					console.log(arr1.length)
					
					var arr2 = new Array(3);
					console.log(arr2[0])
					
					var arr3 = new Array(10,20,30,40,50)
					console.log(arr3[0])
					
					var arr4 = [10,20,30,40]
					console.log(arr4)
					
					var arr5 = [
						[1,2,3],
						[4,5,6],
						[7,8,9],
					];
					var stus = [
						{id:1,name:"张三",age:18},
						{id:2,name:"李四",age:19},
						{id:3,name:"王五",age:20},				
					]
					console.log(stus)
					
					document.write("<table>");
								document.write("<tr>");
								document.write("<td>");
								document.write("学号");
								document.write("</td>");
								document.write("<td>");
								document.write("姓名");
								document.write("</td>");
								document.write("<td>");
								document.write("年龄");
								document.write("</td>");
								document.write("</tr>");
								for (var i in stus) {
									var stu = stus[i]
									document.write("<tr>");
									document.write("<td>");
									document.write(stu.id);
									document.write("</td>");
									document.write("<td>");
									document.write(stu.name);
									document.write("</td>");
									document.write("<td>");
									document.write(stu.age);
									document.write("</td>");
									document.write("</tr>");
								}
								document.write("</table>");
					
								// 练习:
								// 定义一个数组存放一些国家名字 
		</script>
	</body>
</html>